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Hello, I'm having trouble with my truck passing smog on the EVAP test.

(1994 Ford Explorer)
in Newark, CA on January 18, 2012
My trouble codes are 136 & 172. I have already replaced both oxygen sensors, and the EGR valve. Can you help what to do next?
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Popular Answer
of Greg's Orange Auto on January 18, 2012
YOUR CODES INDICATE BANK1 SENSOR 1 IS READING LEAN AND 172 IS LEAN BANK 1 THAT DOES NOT MEAN YOUR SENSOR IS BAD IT MEANS BANK 1 HAS LEAN ISSUES. EX. VAC LEAK, MASS A/F SENSOR, FUEL FILTER, PCM OR WIRING PROBLEMS I THINK YOU NEED TO SEEK HELP FROM SOMEONE WITH A SMOKE MACHINE AND OTHER TEST EQUIP.
on January 19, 2012
Manny,

Don't install any more parts. Check for vacuum leaks with a smoke machine or you can use brake clean sparingly. If you spray a vacuum line and engine revs higher then you found the problem. Intake manifold gaskets leak on the Fords so hit that a couple of times as well.
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